Voice over Internet protocol (VoIP) telephony is a growing means by which to communicate. VoIP operates by taking voice signals (e.g., from a telephone or other input device) and converting them into digital signals for transmission via a computer network, e.g., the Internet. At a receiving end, the digital voice signals are then converted back into analog signals for the called party, either by telephone, computer or other output means.
VoIP offers many advantages over traditional telephone systems. First, VoIP can provide for free telephone communication, even for long distance service. Second, the resources such as bandwidth needed for communications may be significantly reduced, as the packet-based communication of VoIP is far more efficient than the traditional circuit-based switching network of a telephone system.
Different manners of communicating via VoIP have appeared. For instance a consumer can use a traditional telephone to place VoIP calls by using an adapter device, referred to as an analog telephone adapter (ATA), that is coupled to the telephone. The ATA is in turn coupled to a modem, router or other interconnection to the Internet. The ATA typically includes analog-to-digital converter (ADC) circuitry. Other VoIP services may use a specialized Internet protocol (IP) telephone that includes a built-in ADC/digital-to-analog (DAC) or other codec functionality to provide a direct connection to a router or other gateway to the Internet. Still further, VoIP may be effected using computer-to-computer connections in which computers outfitted with an appropriate input device (e.g., a microphone) and output device (e.g., speakers) allows a user to communicate using standard audio components of the system, such as a sound card including codec features. Typically, the computer will also include dedicated software to handle VoIP communications. Certain modems and ATAs include additional telephone-based circuitry, such as subscriber line interface circuitry (SLIC). Such a SLIC is used to interface with the telephone system.
In various VoIP applications, software may be implemented on a computer, for example, to enable the VoIP. Typically, this software is associated with a particular manufacturer of an ATA, IP telephone or other specialized hardware for providing the VoIP telephony. However, as independent software vendors enter the VoIP market with software to perform VoIP telephony, concerns with respect to piracy or other malicious activities are raised.